Try to get a stripe on my shirt texture to follow the curve of the collar
I would try laying out the UVs more organically, than just laying it out in quads. Since they are not displayed on the model that way in the end, I think it's giving it the appearance of being stretched around like that.
Could also be that since you've drawn in the corners on the UV map, that is it simply replicating those corners in your texture. So I would try to round out the lines.
These suggestions could be separate or work in tandem, but it's what I would try. Hope that helps. Good luck!